Knowing that pluto is travelling at 10,604 and the Earth travels 6.28 times faster;
6.28x=10,604 mph (where x is the speed of the earth)
x=10,604/6.28
x=1688.53 mph for the Earth
Double check by multiplying the answer found by 6.28 to see if it gives pluto's speed.
1688.53×6.28=10, 604 mph
Therefore, our solution is correct.
Hope I helped :)